AB1203 DAS28 (DISEASE ACTIVITY SCORE) ELEVATIONS IN PATIENTS WITH RHEUMATOID ARTHRITIS (RA) WHO HAVE COMORBID FIBROMYALGIA ARE EXPLAINED BY ELEVATED TENDER JOINT COUNTS AS MUCH AS BY ELEVATED PATIENT GLOBAL ASSESSMENT
Authors: S. Kannayiram, K. Schroeder, N. Goodson, T. Pincus
Journal: Annals of the Rheumatic Diseases (2022)

Background DAS28 (disease activity score 28) is elevated in the 20-30% of patients with rheumatoid arthritis (RA) who have comorbid fibromyalgia (FM), largely on the basis of tender joint count (TJC) and patient global assessment (PATGL) [rather than swollen joint count (SJC) or erythrocyte sedimentation rate (ESR)]. 1 High DAS28 in the absence of clinical inflammatory activity may suggest inappropriate treatment escalation and/or changes in a treat-to-target approach. Some reports suggest removal of PATGL from criteria for remission 2 . Objectives We analyzed the 4 DAS28-ESR component measures in reports of FM+ or FM- RA patients, to recognize the possible contribution of each to elevated DAS28 in patients with FM. Methods We reviewed reports from a meta-analysis of elevated DAS28 in RA patients with comorbid FM, 1 and conducted a PubMed search for further reports of DAS28-ESR in FM+ or FM- RA patients in routine care. We analyzed reports that presented the 4 individual DAS-28-ESR components in FM+ vs FM- RA patients, calculated overall medians of published mean or median results, and calculated ratios of each component measure in FM+ and FM- patients. Results Eleven reports were identified. Mean disease duration was 5-12.8 years. Median DAS28-ESR of means/medians in FM+ RA patients was 5.3, and &gt;5.1 in 9 of 11 studies, suggesting high disease activity (moderate in 2 studies) (Table 1). By contrast, median DAS28-ESR of means/medians in FM- RA patients was 4.1, moderate (3.2–5.1) in all 11 studies (Table 1). Medians of individual DAS28-ESR components were 28.5 vs 26 for ESR, 3.25 vs 3 for SJC, 12.3 vs 5.5 for TJC, and 62.7 vs 40 for PATGL in FM+ vs FM- RA patients, respectively. Ratios of DAS28 components in FM +/FM - patients were 2.7 for TJC, 1.6 for PATGL, 1.1 for ESR, and 1.0 for SJC. Table 1. DAS28 and component measures In RA patients who have or do not have comorbid fibromyalgia and ratio of means in the two groups (FM+/FM-) MEASURES DAS28 ESR SJC TJC PATGL STUDY FM+/ FM+/ FM+/ FM+/ FM+/ FM+/ FM+/ FM+/ FM+/ FM+/ FM - FM - FM - FM - FM - FM - FM - FM - FM - FM - Ranzolin 5.4, 4.0 1.3 29*,25 1.16 3.5*,2.0* 1.7 9.5*,3* 3.2 76*,40* 1.9 2009 Pollard 6, 4.3 1.4 39,27 1.4 4.0,4.0 1 17,6 2.8 66,40 1.6 2010 Toms 5.3, 3.7 1.4 39.4,28.5 1.4 4.9,3.0 1.6 14.1,2.9 4.9 60.4,32.6 1.8 2010 Zammurrad 2013 5.3, 3.9 1.3 38.9,31 1.2 2.8,1.7 1.6 13.1,4.1 3.2 62.7,38 1.6 Nawito 5.6, 4.5 1.2 38.2,41.8 0.9 2.8,3.0 0.9 12.3,4.5 2.7 38.2,41.8 0.9 2013 Ghib 5.6, 4.6 1.2 23,22 1.1 5.0,6.0 0.8 15,5.5 2.7 66,44.5 1.5 2015* Joharatnam 4.8, 4.4 1.1 19,17 1.1 1.0,1.0 1 11,6 1.8 70,42 1.6 2015* Mian 5.2, 4.1 1.3 20.5,19.1 1.1 1.8,2.8 0.6 15.6,7.3 2.1 57,49.5 1.1 2016 Chakr 5.3, 3.9 1.3 28.5,26 1.1 3.9,2.4* 1.6 10*,3* 3.3 56.5*,31.5* 1.8 2017 Salaffi 4.5, 3.8 1.2 24,32 0.7 3.0,4.0 0.7 12,6 2 80,70 1.1 2018* Provan 5.2, 4.2 1.2 23,21 1.1 8.4,6.4 1.3 10.7,6.4 1.7 55,30 1.8 2019 Median-11 Studies 5.3, 4.1 1.3 28.5,26 1.1 3.2,5.3 1 12.3,5.5 2.7 62.7,40 1.6 * All values were reported means other than medians noted by asterisk (*). Conclusion Mean DAS28-ESR indicated high vs moderate disease activity in 9 of 11 FM+ RA patient groups vs all 11 FM- RA groups, respectively. Among the 4 DAS28 component measures, TJC differed most in FM+ vs FM- RA patients followed by PATGL, while SJC and ESR were similar in both groups. The impact of TJC likely is underestimated as the DAS28 formula weights TJC twice as SJC. Elevated DAS28 in the absence of inflammation in RA FM+ patients may result as much or more from TJC as from PATGL. References [1]Duffield et al Rheumatology (Oxford). 2018;57(8):1453-1460. [2]Ferreira et al J Rheumatol. 2021. Disclosure of Interests None declared